1. Field of the Invention
This invention relates to a method and apparatus for performing operations in limited space work areas.
2. Description of the Prior Art
Many working environments include inaccessible or limited space work areas, such as subterranean keyhole excavation spaces, underground vaults, sewers, tanks, storage bins, diked areas, vessels, silos, and other confined spaces. A confined space generally has limited or restricted means of entry or exit. A confined space is accessible to workers to the extent that it is large enough to enter and perform assigned work and is not designed for continuous occupancy. The hazards associated with a confined space may include storage of hazardous material, usage of hazardous material, hazardous activities or other hazards associated with the external environment.
Many workplaces contain spaces that meet the regulatory definitions of a confined space because their configurations impede the activities of workers who must enter and exit the space to perform work. Also, workers encounter workplaces where work is to be performed in a space that is completely inaccessible to the extent that the workers must operate tools from a position remote from or out of the inaccessible area. In many instances, a worker will face increased risk of serious physical injury, entrapment, engulfment, exposure to hazardous materials, or hazardous atmospheres. Hazardous atmospheres include atmospheres that include flammable, toxic, irritating, or corrosive components.
Some confined spaces are “permit-required” confined spaces. Permit-required confined spaces may contain or have the potential to contain a hazardous atmosphere. Permit-required confined spaces may also contain a material that has the potential to engulf an entrant. Permit-required confined spaces may also have an internal configuration that might cause an entrant to be trapped or asphyxiated by inwardly converging walls or by a floor that slopes down-ward and tapers to a smaller cross section. Permit-required confined spaces may contain any other recognized serious safety or health hazards.
The need to minimize disruption to the surrounding landscape has led to the development of minimally invasive technology or subterranean “keyhole” excavations. Subterranean keyhole excavation involves performing work above ground using extension tools to access valves, couplings, and the like on a subterranean natural gas pipeline or water line. The objective of subterranean keyhole excavation is to perform as much work underground with the smallest possible ground opening. A small opening is cut in the pavement, so that earthen material around the pipe is excavated to provide access to a particular section of the pipeline. The target holes are typically 18 inches in diameter, but may be as small as twelve inches in diameter. Typically, a valve or some fixture is replaced or repaired. These operations are performed by using tools that extend through the keyhole to the underground pipeline.
Various extension tools have been disclosed for performing conventional operations. U.S. Patent Application Publication No. 2004/0025649 discloses a wrench extension that includes an elongated member, a grip, and a pair of brackets extending from the elongated member. The grip is positioned on one end of the elongated member. One of the brackets is positioned on the opposite end. The other bracket is positioned in spaced apart manner from the first bracket, so that the brackets receive a wrench or other suitable tool. The brackets are welded onto the member.
U.S. Pat. No. 5,396,820 discloses an extensible wrench handle having a removable wrench head. The handle includes a tubular member with a telescoping extension extending therefrom. The extension is connected to the tubular member through a conventional fastening mechanism. The wrench head is pivotally attached to the extension.
U.S. Pat. No. 6,443,039 discloses a wrench having a pair of pivotally connected driving stems. One of the driving stems includes a yoke. A pin inserts through the yoke to connect the driving stems to one another.
U.S. Pat. No. 6,095,016 discloses a screw and bolt clamp drive. The drive includes a rotating elongated cylindrical rod. The rod receives a conventional power drill having a conventional chuck. The rod connects to a base frame on the opposite end. The base frame includes receives a pair of block jaws for gripping screws or bolts.
U.S. Pat. No. 5,927,161 discloses an adjustable tool extension. The extension includes a plurality of cylindrical telescoping members. A first member includes an upper end that includes a recess for receiving a drive end of a ratchet. A second member includes a drive end that can be coupled to various tools. A third member connects the first member to the second member.
Extension handles having clevis-type connections have been disclosed for performing conventional operations. U.S. Pat. No. 3,186,264 discloses an extendable wrench. The wrench includes a handle, a handle shaft, a head shaft, and a head. The handle shaft is threadedly attached to the head shaft. The head includes a socket holder that attaches to the head with a pin.
U.S. Pat. No. 5,279,189 discloses an extension tool for attaching and removing threaded components. The tool includes an arm that includes a handle, a connecting portion, and a member that connects to a fitting. A pin connects the fitting to the member.
Various extendable valve operators or valve keys for underground operations have also been disclosed. U.S. Pat. No. 5,638,590 discloses a tool for removing and replacing an operating nut on a subterranean gate. The tool includes an operating nut, a shaft, a handle, and a slide.
U.S. Pat. No. 6,776,068 discloses a valve operator for opening and closing valves in underground operations. The valve operator includes a lower member, an upper member, and a pin connecting the lower member to the upper member. The lower member includes a lower end portion that releasably engages an underground valve nut.
U.S. Pat. No. 6,364,285 discloses an extendable utility valve key having a clevis-type connection. The key includes a tubular member having a t-shaped handle. The tubular member receives a second member that connects to one of a plurality of base portions. The tubular member connects to the second member via a clevis-type connection. Accordingly, while it is known to make extended valve operators and valve keys, there is a need for an improved extension tool for operation within limited space work areas.